Field of Endeavor
The teachings in accordance with exemplary and non-limiting embodiments of this disclosure relate generally to a camera system and an auto-focusing method thereof.
Background
This section provides background information related to the present disclosure which is not necessarily prior art.
In general, a compact small camera module is applied to mobile terminal devices such as camera modules, PDAs (Personal Digital Assistants), and smart phones and various IT (Information Technology) devices.
The camera module is manufactured using an image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and manufactured to adjust a camera focus for adjustment of size of an image. Furthermore, the camera module includes a plurality of lens, and is mounted with a driving source to move the lenses, whereby an optical distance is adjusted by changing a relative distance of each lens.
Recently, concomitant with development of technologies, a high pixel camera module is being developed, and this camera module is equipped with auto focus function automatically adjusting a focus of an object.
The conventional auto focus method includes a mountain climb control method and a full scan control method
In the conventional methods, a lens is moved stage by stage, searches for a changed image relative to a previous image, performs a fine search again and stops at a point of the find search.
At this time, errors are generated on auto focus accuracy and completion time in response to frame speed, at which portion the auto focus is centered and changed degree of an object.
Furthermore, there is another disadvantage in the conventional methods in that an auto focusing time is lengthened because the auto focusing is performed by the multiple-stage searching.